diff options
Diffstat (limited to 'drivers/infiniband')
| -rw-r--r-- | drivers/infiniband/core/user_mad.c | 87 |
1 files changed, 63 insertions, 24 deletions
diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index d61f544f19e..5ea741f47fc 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -31,7 +31,7 @@ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. * - * $Id: user_mad.c 2814 2005-07-06 19:14:09Z halr $ + * $Id: user_mad.c 4010 2005-11-09 23:11:56Z roland $ */ #include <linux/module.h> @@ -110,12 +110,13 @@ struct ib_umad_device { }; struct ib_umad_file { - struct ib_umad_port *port; - struct list_head recv_list; - struct list_head port_list; - spinlock_t recv_lock; - wait_queue_head_t recv_wait; - struct ib_mad_agent *agent[IB_UMAD_MAX_AGENTS]; + struct ib_umad_port *port; + struct list_head recv_list; + struct list_head port_list; + spinlock_t recv_lock; + wait_queue_head_t recv_wait; + struct ib_mad_agent *agent[IB_UMAD_MAX_AGENTS]; + int agents_dead; }; struct ib_umad_packet { @@ -144,6 +145,12 @@ static void ib_umad_release_dev(struct kref *ref) kfree(dev); } +/* caller must hold port->mutex at least for reading */ +static struct ib_mad_agent *__get_agent(struct ib_umad_file *file, int id) +{ + return file->agents_dead ? NULL : file->agent[id]; +} + static int queue_packet(struct ib_umad_file *file, struct ib_mad_agent *agent, struct ib_umad_packet *packet) @@ -151,10 +158,11 @@ static int queue_packet(struct ib_umad_file *file, int ret = 1; down_read(&file->port->mutex); + for (packet->mad.hdr.id = 0; packet->mad.hdr.id < IB_UMAD_MAX_AGENTS; packet->mad.hdr.id++) - if (agent == file->agent[packet->mad.hdr.id]) { + if (agent == __get_agent(file, packet->mad.hdr.id)) { spin_lock_irq(&file->recv_lock); list_add_tail(&packet->list, &file->recv_list); spin_unlock_irq(&file->recv_lock); @@ -326,7 +334,7 @@ static ssize_t ib_umad_write(struct file *filp, const char __user *buf, down_read(&file->port->mutex); - agent = file->agent[packet->mad.hdr.id]; + agent = __get_agent(file, packet->mad.hdr.id); if (!agent) { ret = -EINVAL; goto err_up; @@ -480,7 +488,7 @@ static int ib_umad_reg_agent(struct ib_umad_file *file, unsigned long arg) } for (agent_id = 0; agent_id < IB_UMAD_MAX_AGENTS; ++agent_id) - if (!file->agent[agent_id]) + if (!__get_agent(file, agent_id)) goto found; ret = -ENOMEM; @@ -530,7 +538,7 @@ static int ib_umad_unreg_agent(struct ib_umad_file *file, unsigned long arg) down_write(&file->port->mutex); - if (id < 0 || id >= IB_UMAD_MAX_AGENTS || !file->agent[id]) { + if (id < 0 || id >= IB_UMAD_MAX_AGENTS || !__get_agent(file, id)) { ret = -EINVAL; goto out; } @@ -608,21 +616,29 @@ static int ib_umad_close(struct inode *inode, struct file *filp) struct ib_umad_file *file = filp->private_data; struct ib_umad_device *dev = file->port->umad_dev; struct ib_umad_packet *packet, *tmp; + int already_dead; int i; - for (i = 0; i < IB_UMAD_MAX_AGENTS; ++i) - if (file->agent[i]) - ib_unregister_mad_agent(file->agent[i]); + down_write(&file->port->mutex); + + already_dead = file->agents_dead; + file->agents_dead = 1; list_for_each_entry_safe(packet, tmp, &file->recv_list, list) kfree(packet); - down_write(&file->port->mutex); list_del(&file->port_list); - up_write(&file->port->mutex); - kfree(file); + downgrade_write(&file->port->mutex); + + if (!already_dead) + for (i = 0; i < IB_UMAD_MAX_AGENTS; ++i) + if (file->agent[i]) + ib_unregister_mad_agent(file->agent[i]); + up_read(&file->port->mutex); + + kfree(file); kref_put(&dev->ref, ib_umad_release_dev); return 0; @@ -848,13 +864,36 @@ static void ib_umad_kill_port(struct ib_umad_port *port) port->ib_dev = NULL; - list_for_each_entry(file, &port->file_list, port_list) - for (id = 0; id < IB_UMAD_MAX_AGENTS; ++id) { - if (!file->agent[id]) - continue; - ib_unregister_mad_agent(file->agent[id]); - file->agent[id] = NULL; - } + /* + * Now go through the list of files attached to this port and + * unregister all of their MAD agents. We need to hold + * port->mutex while doing this to avoid racing with + * ib_umad_close(), but we can't hold the mutex for writing + * while calling ib_unregister_mad_agent(), since that might + * deadlock by calling back into queue_packet(). So we + * downgrade our lock to a read lock, and then drop and + * reacquire the write lock for the next iteration. + * + * We do list_del_init() on the file's list_head so that the + * list_del in ib_umad_close() is still OK, even after the + * file is removed from the list. + */ + while (!list_empty(&port->file_list)) { + file = list_entry(port->file_list.next, struct ib_umad_file, + port_list); + + file->agents_dead = 1; + list_del_init(&file->port_list); + + downgrade_write(&port->mutex); + + for (id = 0; id < IB_UMAD_MAX_AGENTS; ++id) + if (file->agent[id]) + ib_unregister_mad_agent(file->agent[id]); + + up_read(&port->mutex); + down_write(&port->mutex); + } up_write(&port->mutex); |